The four beasts of Daniel chapter 7 are four kingdoms, each of which dominates the world, successively, in the centuries leading up to the reign of the Antichrist.

[Daniel]
{7:3} And four great beasts, different from one another, ascended from the sea.

The sea represents the great sea of peoples in the world, in various nations, languages, cultures, and regions. The beasts are kingdoms. Each beast is called “great” because it dominates the other nations of the world, to some extent.

{7:4} The first was like a lioness and had the wings of an eagle. I watched as its wings were plucked off, and it was raised from the earth and stood on its feet like a man, and the heart of a man was given to it.

The wings of the eagle represent the air power of the United States used to establish this kingdom. World War 3 sees the Arab Muslim nations of the Middle East and northern Africa conquer Europe and rule over a vast territory. In World War 4, the U.S. and Allies free Europe and conquer the extremists. Subsequently, the great Catholic monarch rules over the entire territory once held by the extremists. So World War 3 establishes a kingdom for the great Catholic monarch.

This kingdom is the lioness. The U.S. is not part of that kingdom, which is why the wings of the eagle are removed. This beast, established by two terrible wars, becomes a reasonable faithful kingdom, and so it is described as turning into a man, and as having the heart of a man (reason and faith). This occurs during the 21st century.

{7:5} And behold, another beast, like a bear, stood to one side, and there were three rows in its mouth and in its teeth, and they spoke to it in this way: “Arise, devour much flesh.”

In the 22nd century, Russia (the bear) rises in power and dominates the other nations of the worl, economically, by means of agriculture, and militarily. Russia will produce much of the world’s animal-source foods, giving the nation much money. China and the U.S. will not be superpowers during that time.

{7:6} After this, I watched, and behold, another like a leopard, and it had wings like a bird, four upon it, and four heads were on the beast, and power was given to it.

In the 23rd century, an alliance of four regions — China, Africa (except for the northern part), India, and one other region — cast off the dominance of Russia to become the sole superpower in the world. They do this by means of air power (“wings like a bird”).

{7:7} After this, I watched in the vision of the night, and behold, a fourth beast, terrible yet wondrous, and exceedingly strong; it had great iron teeth, eating yet crushing, and trampling down the remainder with his feet, but it was unlike the other beasts, which I had seen before it, and it had ten horns.

In the 24th century (2300’s), the world becomes divided into ten sets of nations only: ten kingdoms which comprise all the nations and peoples of the world. These ten kingdoms rule the world as if one beast. It is a time of great sinfulness in the world. Of the ten, only the southern part of the great monarch’s kingdom tolerates religion: Christianity, Judaism, Islam. The other kingdoms are hostile to all religion. Each kingdom has one ruler, which are the ten horns.

{7:8} I considered the horns, and behold, another little horn rose out of the midst of them. And three of the first horns were rooted out by its presence. And behold, eyes like the eyes of a man were in this horn, and a mouth speaking unnatural things.

The Antichrist becomes one of the ten kings, over the kingdom of the North (Europe), in the early 25th century. He at first has little power. He then defeats three kings: South, Meridian (Africa), East (China), in order to become the ruler of all ten kingdoms. For, once he controls the four most powerful of the ten, the other six kingdoms cannot withstand him. He then proclaims himself to be a god.

This explains why the Return of Christ cannot occur for this generation (21st century). These kingdoms must rise and fall before the Antichrist has his nearly seven year reign. Only then can Jesus return, after all that Sacred Scripture has prophesied has been fulfilled.